Each point in the chain supports the weight of all the mass below it.
At the bottom end of the chain, the weight is (175 x 9.8) = 1,715 N .
At the top of the chain, the weight is (175 + 12) x (9.8) = 1,833 N .
The tension in the chain varies linearly from 1,715N at the bottom
to 1,833N at the top.